[CareerCup] 17.10 Encode XML 编码XML - Grandyang - 博客园
17.10 Since XML is very verbose, you are given a way of encoding it where each tag gets mapped to a pre-defined integer value. The language/grammar is as follows:
Element --> Tag Attributes END Children END
Attribute --> Tag Value
END --> 0
Tag --> some predefined mapping to int
Value --> string value END
For example, the following XML might be converted into the compressed string below (assuming a mapping of famiLy -> l, person ->2, frstName ->3, LastName -> 4j state -> 5).
<family lastName="McDowell" state="CA">
<person firstName="Gayle">Some Message</person>
</family>
Becomes:
1 4 McDowell 5 CA 0 2 3 Gayle 0 Some Message 0 0
Write code to print the encoded version of an XML element (passed in E Lament and Attribute objects).
这道题让我们给XML编码,那么我们可以用OOD的方法来实现,建立Attribute类和Element类,其中一个Element中可以包含多个Attribute,然后就是写encode函数,我们可以利用重载特性来写多个encode函数,需要注意的是,在encode到字符串中包含0的时候需要特殊处理,因为题目中说END都要换成0,为了不引起歧义,我们在字符串中出现0的地方前面都加一个\,变成\0,但是\0又表示空格,所以我们需要把所有的0变成\\0,可以用v = v.replace("0", "\\0"); 不得不说的是Java中对字符串的处理实在太强大了,集成了诸如replace, trim, split这样方便又常用的函数,而C++的STL却木有这些功能函数,还是Java叼啊。
We repeatedly call encode () on parts of the XML structure, handling the code in slightly different ways depending on the type of the XML element.
17.10 Since XML is very verbose, you are given a way of encoding it where each tag gets mapped to a pre-defined integer value. The language/grammar is as follows:
Element --> Tag Attributes END Children END
Attribute --> Tag Value
END --> 0
Tag --> some predefined mapping to int
Value --> string value END
For example, the following XML might be converted into the compressed string below (assuming a mapping of famiLy -> l, person ->2, frstName ->3, LastName -> 4j state -> 5).
<family lastName="McDowell" state="CA">
<person firstName="Gayle">Some Message</person>
</family>
Becomes:
1 4 McDowell 5 CA 0 2 3 Gayle 0 Some Message 0 0
Write code to print the encoded version of an XML element (passed in E Lament and Attribute objects).
这道题让我们给XML编码,那么我们可以用OOD的方法来实现,建立Attribute类和Element类,其中一个Element中可以包含多个Attribute,然后就是写encode函数,我们可以利用重载特性来写多个encode函数,需要注意的是,在encode到字符串中包含0的时候需要特殊处理,因为题目中说END都要换成0,为了不引起歧义,我们在字符串中出现0的地方前面都加一个\,变成\0,但是\0又表示空格,所以我们需要把所有的0变成\\0,可以用v = v.replace("0", "\\0"); 不得不说的是Java中对字符串的处理实在太强大了,集成了诸如replace, trim, split这样方便又常用的函数,而C++的STL却木有这些功能函数,还是Java叼啊。
We repeatedly call encode () on parts of the XML structure, handling the code in slightly different ways depending on the type of the XML element.
void encode(Element root, StringBuilder sb) {
encode(root.getNameCode(), sb);
for (Attribute a : root.attributes) {
encode(a, sb);
}
encode("0", sb);
if (root.value != null && root.value != "") {
encode(root.value, sb);
} else {
for (Element e : root.children) {
encode(e, sb);
}
}
encode("0", sb);
}
void encode(String v, StringBuilder sb) {
sb.append(v);
sb.append(" ");
}
void encode(Attribute attr, StringBuilder sb) {
encode(attr.getTagCode(), sb);
encode(attr.value, sb);
}
String encodeToString(Element root) {
StringBuilder s b = new StringBuilder();
encode(root, sb);
return s b.toString();
}
public class Attribute { public String tag; public String value; public Attribute(String t, String v) { tag = t; value = v; } public String getTagCode() { if (tag == "family") { return "1"; } else if (tag == "person") { return "2"; } else if (tag == "firstName") { return "3"; } else if (tag == "lastName") { return "4"; } else if (tag == "state") { return "5"; } return "--"; } } import java.util.ArrayList; public class Element { public ArrayList<Attribute> attributes; public ArrayList<Element> children; public String name; public String value; public Element(String n) { name = n; attributes = new ArrayList<Attribute>(); children = new ArrayList<Element>(); } public Element(String n, String v) { name = n; value = v; attributes = new ArrayList<Attribute>(); children = new ArrayList<Element>(); } public String getNameCode() { if (name == "family") { return "1"; } else if (name == "person") { return "2"; } else if (name == "firstName") { return "3"; } else if (name == "lastName") { return "4"; } else if (name == "state") { return "5"; } return "--"; } public void insert(Attribute attribute) { attributes.add(attribute); } public void insert(Element child) { children.add(child); } } public class j { public static void encode(String v, StringBuffer sb) { v = v.replace("0", "\\0"); sb.append(v); sb.append(" "); } public static void encodeEnd(StringBuffer sb) { sb.append("0"); sb.append(" "); } public static void encode(Attribute attr, StringBuffer sb) { encode(attr.getTagCode(), sb); encode(attr.value, sb); } public static void encode(Element root, StringBuffer sb) { encode(root.getNameCode(), sb); for (Attribute a : root.attributes) { encode(a, sb); } encodeEnd(sb); if (root.value != null && root.value != "") { encode(root.value, sb); } else { for (Element e : root.children) { encode(e, sb); } } encodeEnd(sb); } public static String encodeToString(Element root) { StringBuffer sb = new StringBuffer(); encode(root, sb); return sb.toString(); } public static void main(String args[]) { Element root = new Element("family"); Attribute a1 = new Attribute("lastName", "0"); Attribute a2 = new Attribute("state", "CA"); root.insert(a1); root.insert(a2); Element child = new Element("person", "Some Message"); Attribute a3 = new Attribute("firstName", "Gayle"); child.insert(a3); root.insert(child); String s = encodeToString(root); System.out.println(s); } }Read full article from [CareerCup] 17.10 Encode XML 编码XML - Grandyang - 博客园